How to center something vertically on screen when using UINavigationController on iOS?

I've got a UIView defined in IB within a UIViewController, and I have placed completely centered (vertical and horizontal) an activity spinner. 开发者_开发技巧 This all looks great, except in practice I use it by pushing the UIViewController on to a UINavigationController - hence, it displays "pushed down" my screen 50 pixels or whatever, so my spinner is no longer centered.

How do you address this? I want the same code to work on all iOS devices. I don't mind adding it programatically - maybe I need to? But I don't know how to make use of screen size vs view size vs nav view size and then end up with "local" coordinate frame for the spinner.

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Try setting its center property to the same value of the hosting view's one.
So in viewDidLoad, do something like :

myIndicator.center = self.view.center;

This should make it, but you can also calculate it with few instructions.